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PAINTING 



INSTRUCTION PAPER 



PKEPARED BY 



Ai^VAH HoRTON Sabin, M. S., 

Lecturer in New York University, 

Author of "The Technology of Paint and Varnish," etc. 

American Society of Mechanical Engineers. 



AMERICAN SCHOOL OF CORRESPONDENCE 

CHICAGO ILLINOIS 

U.S.A. 



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5 



iUBRART ofOONiiriESJ 
IwoMMs Mecei>wi 
JUN 13 1908 



copyright 1908 by 
American School of Correspondence 



Entered at Stationers' Hall, London 
All Risfhts Reserved 



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PAINTING 



Introductory. The first thing a man wishes to know when he 
contemplates painting a house, is the cost. This will obviously depend 
on the cost of labor, of materials, and the kind of materials chosen. 
The outside of a house is painted, either in whole or in part ; the interior 
may be painted or varnished. Some houses have their walls partly 
covered with shingles; these shingles are sometimes painted, and 
sometimes — in fact, often — left unpainted ; but what is called the trim — 
that is, the boarding about the eaves, windows, doors, the base-board, 
and corner-pieces — is painted. Shingles, either wall or roof, are often 
stained with a creosote stain consisting of a coloring matter dissolved 
or suspended in a liquid called creosote, which is applied for the purpose 
of preserving them; and though instances can be cited in which wall- 
shingles that were never stained are still doing good service although 
believed to be now two hundred and fifty years old, yet the use of 
creosote will undoubtedly prolong the life of modern, sawn shingles, as 
it is noxious to insect Ufe and a powerful deterrent of natural decay. 
The color of unpainted new shingles is generally disliked; but after 
four or five years wall-shingles take on a beautiful, soft color. The 
question of staining shingles is a matter of taste. 

Most houses are exteriorly painted with paint based on white lead 
or zinc. Some idea of the cost may perhaps be gained from the 
following considerations : 

White lead is sold either ground with a little oil to a thick paste, or — 
less commonly — in the dry state. 

A mixture of 100 pounds of paste white lead with 5 gallons of linseed 
oil, makes 6^ gallons of paint, weighing 21.3 lbs. per gal. 

Approximate figures are: 15 lbs. paste lead and 6.3 lbs. oil equals 1 gal. 
(1 gal. oil equals 7.7 lbs.); 14 lbs. dry lead and 7^ lbs. oil equals 1 gal. 

A mixture of 100 pounds of white zinc and 85 gal. oil, makes 10| gal. of 
paint; 12 lbs. zinc and 1 gal. oil make 1.3 gal., or 9.5 lbs. zinc and 5.7 lbs. 
oil make 1 gal. white zinc paint weighing 15.2 lbs. Dark -colored paints 
made from iron oxides, ochers, and the like, weigh 12 to 14 pounds per gallon; 
but exact figures cannot be given, as the raw materials differ greatly. 

Here should be noted the difference between the priming coat and 

the succeeding ones. A priming coat is the first coat applied to the 



2 PAINTING 

■ •— 

clean wooden surface ; it differs from the other coats in containing more 
oil, because the wood will soak up the oil and leave the coloring matter 
of the paint on the outside. 

To make the paint for the priming coat, take a gallon of the paint 
already described and mix with it a gallon of raw linseed oil. Paint 
thus made is, of course, lower in price; it is also much thinner; but 
such is the absorbent power of the wood, that the priming paint does 
not cover as much surface as the succeeding coats per gallon. A 
gallon of this thin priming coat covers 300 to 400 sq. ft., while a gallon 
of second or third-coat paint, well brushed out, will cover about twice 
this surface; this is because the surface for all but the first coat is hard 
and non-absorbent. Priming coats are used for both outside and 
inside work, as will be described later. 

The dark-colored paints are usually cheaper than those made 
from lead and zinc, and if made of good materials are not inferior in 
durability; the extraordinary claims made by the zinc and lead manu- 
facturers are to be received with much doubt. Some of the dark- 
colored paints are the most durable that can be applied on wood. The 
chief cost of painting is, however, that of labor, which varies according 
to locality and other conditions, seldom being less than twice that of 
materials. 

For light-colored paints, it is lietter to use raw linseed oil to which 
pale japan dryer may be added, as described later; for dark colors, 
either this or boiled oil, boiled oil being darker in color. The cost is 
practically the same; also the durability. 

On inside work may be used either oil or enamel paint, as 
described later, the former being the cheaper, the latter the handsomer 
and slightly more durable; or the wood may be finished in its natural 
color, by varnishing it either with an oleo-resinous varnish or with 
shellac varnish. The oleo-resinous varnishes darken the wood very 
appreciably, while white shellac varnish keeps it more nearly in its 
natural color; although the latter does not prevent the natural darken- 
ing action of light, it may retard it. Shellac varnish is the more expen- 
sive finish of the two, if well applied. What is sometimes called oil 
finish generally consists in the application of a cheap varnish called 
hard oil, which is usually made of common rosin, linseed oil, and ben- 
zine. Its only merit is that it is cheap. 



PAINTING 



It would indeed be possible to apply neither paint nor varnish, 
but merely to saturate the wood with oil, and this would be truly an 
oil finish; it would, however, make the wood dark and dingy, and 
would readily retain dirt, and is a practice seldom followed except 
sometimes on floors — especially kitchen floors — and sink shelves. 
These are at frequent intervals oiled ^^•ith a mixture of equal parts 
boiled oil and turpentine. 

It is the purpose of this Instruction Paper to describe only good 
and approved methods. It will readily be understood, and will 
certainly be observed in practice, that these methods may be abbre- 
viated by the omission of some details that are here specified as desir- 
able. For instance, it is difficult to get interior finish sandpapered or 
rubbed between coats, even if so contracted; but this is the right 
practice. Two coats of varnish often have to serve in the place of 
four. No one, however, needs to be told these things. The methods 
herein described are not luxurious or extravagant; they are, on fairly 
good houses, truly economical; and we are not considering temporary 
structures. 

It is not uncommon to find part of a house, as the living rooms, 
finished in varnish, and the kitchen and pantry painted with oil 
paints, which are lighter in color and more easily renewed. The 
sleeping rooms, on the other hand, are often finished in enamel paints, 
because color effects are desired to harmonize with the furnishings; 
and bathrooms are almost always done in enamel for sanitary con- 
siderations. The taste and inclination of the owner are to be con- 
sulted in regard to all these matters. 

PAINTERS' SUPPLIES 

Pigments and Vehicles. Paint is a mixture of a finely-divided 
solid substance with a liquid which, when spread on a solid surface 
with a brush or otherwise, will adhere and in a short time form— by 
evaporation, or more commonly by oxidation— a somewhat hard and 
tough film. The finely divided solid is called the pigment; the liquid 
part, the vehicle. The most common vehicle is linseed oil. This is 
an oil obtained by pressure (or extraction by solvents) from flaxseed. 
AVhen spread out in a film and exposed to the air, linseed oil is con- 
verted into a tough, leathery, elastic substance called linoxin, insoluble 
in water and all common solvents. This change is brought about by 



4 PAINTING 

'- '■ • — 

absorption and chemical union of the oxygen of the air, whereby the 
weight of the oil is increased about one-fifth or one-sixth. It is there- 
fore a mistake to suppose that oil paint gets dry as whitewash does, 
by the evaporation of the li(|uid. Instead of that, it gets heavier. 
There are some other vegetable oils which have this property in some 
degree, but none which are used for paints to any considerable extent; 
some are used a little for artists' colors. 

Linseed oil should stand at least a month or two before using. 
It should then be perfectly free from sediment or cloudiness; if it is not 
so, this is a sign that the oil has not been properly aged, and such oil 
is not fit for making paints. In this natural state, it is called raiv oil; 
and the price of linseed oil as commonly quoted refers to raw oil. 
Boiled oil is this raw oil which has been heated, usually to 450° or 500° 
F., with the addition of a small amount of oxide of lead or oxide of 
manganese, or a mixture of the two (occasionally some other lead or 
manganese compounds are used). Boiled oil is darker (browner) in 
color than raw oil, but differs fn^m it chiefly in that it dries five to ten 
times as rapidly. A thin film of raw oil on a glass or metal surface 
will dry at ordinary temperatures in five or six days, so as to feel no 
longer greasy; but boiled oil will do the same in a day or half a day. 
Oil dries best in warm, dry weather and out of cloors. 

The pigment is mixed witli the oil by stirring the two together. 
This is usually done V)y power, in a vessel called a paint mixer. The 
mixture should then be run through a paint mill; some paint mills are 
of steel, but the best have a pair of mill-stones, between which the 
paint is ground and most tlioroughly mixed. Paints mixed in this 
manner are much better than those wliich are mixed only by stirring. 

Besides oil and j)igmcnt, paint sometimes contains a volatile thin- 
ner, the most important thinners being turpentine and benzine. Tur- 
pentine is a well-known essential oil, volatile, boiling at about 320° F., 
but evaporating at ordinary t(>mperatures when exposed to the air. 
Benzine is a mineral oil, lighter than kerosene and heavier than gaso- 
line; the kind used in paint and varnish is called "62-degree 
benzine," its specific gravity being G2° on the Baume scale for liquids 
lighter than water. Linseed oil weighs 7.7 lbs. per gallon; turpen- 
tine, 7.2 lbs.; and 62° benzine, G.l lbs. But linseetl oil is sold by the 
oil makers and dealers on the basis of 7.5 lbs. per gallon. 



PAINTIN'G 



A dryer, in some form, is an essential ingredient of oil paint. 
A dryer is a compound of lead or manganese (generally both), soluble 
in oil, and is usually sold, under the name of 'paint dryer or 'paint japan, 
as a solution of such material in a mixture of oil, turpentine, and ben- 
zine. It Is usually of such strength that an addition of from 5 to 10 
per cent of it to a raw-oil paint will make it dry in from six to twelve 
hours sufficiently to be carefully handled. Paints are not dry enough 
to use, until they have stood four times as long as this ; and they con- 
tinue to harden for months. The strongest drying japans are dark in 
color; but such are more injurious to the durability of the paint than 
those which are paler, especially if the latter do not contain rosin. 
The buyer should always ask for a guarantee that the dryer is free 
from rosin, if great durability in the paint is needed. Not more than 
10 per cent of any dryer or japan should ever be used in any paint. 
Slowly drying paints are more durable than quick ones. 

In house painting, the white pigments are the most important, 
because they are the base of all light-colored paints. The most 
important white pigment is white lead. This is sold either as a dry 
powder, or (more commonly) as paste white lead, which is made- of 
90 lbs. dry white lead and 10 lbs. linseed oil. This can be thinned 
with boiled oil to make a white paint. White lead is a very heavy 
pigment; and with a given quantity of oil, more of it can be mixed 
than of any other pigment, except red lead. It has great opacity, 
or covering power. It is discolored by gases containing sulphur, 
becoming brown or black ; and unless exposed to fairly strong light, it 
becomes yellowish even in pure air. It is better if it has been mixed 
with the oil for some time — a year or more. 

White zinc is a somewhat purer white than white lead; not so 
opaque. Three coats of lead are reckoned equal to five coats of zinc. 
It becomes harder than lead, but is somewhat liable to peel off; while 
lead, after exposure to the air for a long time, becomes dry and powdery 
on its surface, and chalks. 

A mixture of two parts of lead and one of zinc is much liked. 
VAnc-lead, however, is the name of an entirely different pigment, made 
by furnacing ores containing about equal parts of lead and zinc, 
in which the lead is present as a sulphate. This pigment is free from 
the liability to turn brown if exposed to sulphur gases; it is said to be 
not quite so pure a white as the preceding. It is a comparatively new 



PAINTING 



pigment, but is coming rapidly into use, being somewhat cheaper than 
the others. Lithopmic is another white pigment of considerable merit. 

Adulterants. All these pigments may be adulterated with 
barytcs, or with terra alba (sulphate of lime), sometimes with whiting 
(carbonate of lime). These adulterants are powdered minerals. 
Barytes is a good pigment, so far as protective action goes; and 
terra alba is thought by some good authorities to be unobjectionable; 
but whiting is injurious. All of them are transparent in oil, and 
lessen the opacity or whitening power of the paint. 

From these white paints, colored paints are made- by adding 
tinting colors, of which the yellow is chiefly chrome yelloiv, or chromate 
of lead; the blue may be either idtramarine or prussian blue; and the 
green is chrome green, a mixture of chrome yellow and prussian blue. 
The reds are (in house paints) made from coal-tar colors, and most of 
them are now fairly fast to light. Some dull yellow colors are made from 
ochcrs, which are clays tinted with iron oxides, roasted and ground. 
These are permanent colors. 

The dark-colored paints may not contain lead or zinc at all. The 
deep yellows, greens, and blues are made from the colors already 
named as tinting colors, none of which are entirely fast to light; the 
dark reds and browns are chiefly iron oxides, which are a valuable class 
of paints, very permanent on wood. The blacks are either lamp- 
black or drop-black (bone-black.) and other carbon colors; and these 
are often added in small quantity to secure some desired tone or shade 
of color. 

The zinc and lead pigments have some action on oil, and in their 
case it is considered the best practice to apply thin coats; but the dark 
pigments do not act on oil, and, of these, thick coats are best for dura- 
bility. 

Paint and Varnish Brushes. A brush that has only a low price 
to recommend it will prove a poor investment. If properly cared for, 
brushes last a long time, and it pays to have good ones. The first sign 
of a good brush is uniform quality from outside to center. Inferior 
brushes have inferior bristles in the middle, and some poor brushes 
are actually hollow. For ordinary oil painting, the bristles on a large 
new brush should be five or six inches long, uniformly flexible, and as 
stiff as can be.found ; they will be flexible enough an^'Avay, but all should 
be alike. 



PAINTING 



Paint brushes are round, fat, or oval. A favorite brush for 
ordinary outside work is what is called a pound brush, a large, round 
brush with stiff bristles six inches long. Such a brush should be 
bridled when it is new — a "bridle" being a piece of cord wound around 
the bristles to shorten their effective length; as the bristles become 
w^orn off, the bridle may be removed. A 2j-inch oval brush (2h 
inches wide) is a highly satisfactory tool to use in general painting, 
and is the brush recommended by the paint committee of the iVmerican 
Society for Testing Materials. It is worth noting that this committee, 
made up equally of expert paint manufacturers and experts employed 
by the large consumers, unanimously agreed that no larger brush than 
this should be used in making paint tests. 

The use of brushes five inches wide is common for outside work; 
but while such brushes may be had of the best quality, they are heavy 
and laborious to use, and the workman who uses such a brush will not 
brush the paint sufficiently to get the best result. If a flat brush is 
used, it should not exceed 3^ inches in width; and three inches is 
better. A good 2^-inch oval varnish brush is a most excellent brush 
for all large work in either paint or varnish. The painter should also 
have a good l|-inch oval brush for smaller work, and a number of 
round or oval brushes, called sa^h tools, of different smaller sizes, for 
more delicate work, such as sash and frame painting. Stiff-bristle 
brushes, which have been worn off short, are suitable for such work as 
rubbing-in filling. For varnishing large surfaces, flat bristle brushes 
22 inches wide are good ; also similar ones 2 inches, 1 h inches, and 1 
inch wide are useful. All flat brushes should have chiseled edges. 
For flowing varnish, it is necessary to have thick, flat, camel's-hair 
brushes, running up to 3^ inches in width, although most house 
varnishing may be done with brushes not over 2k inches wide. 

Besides paint brushes, the workman will need some ordinary 
scrubbing brushes and one or two painter's dusting brushes, to have the 
surface properly cleaned. 

Steel-wire brushes, with stiff steel wire instead of bristles, shaped 
like scrubbing brushes, are used for cleaning off old paint and for 
cleaning structural metal work. These are of various sizes; and the 
steel wires are of different lengths and sizes, hence differing in stiffness. 
They may be had at hardware stores. 

Care of Brushes Hair and bristle brushes must be kept clean 



PAINTING 



and soft; this can be done by care and faithfulness. They should 
not be allowed to become dry with paint or varnish in them. To 
prevent this, wash them out in oil or turpentine as soon as you are 
through using them; or they may be left in the paint or varnish for a 
few days. They may be kept over night by wrapping them very 
closely in paper if they have been used in a slow-drying material; in 
this way they may be carried from one place to another. Brushes 
should not be left to dry with even clean oil or turpentine in them; if 
they are to be put away, they should be well washed first with soap 
and water, then with clean water, then hung up until thoroughly dry. 

In use, brushes are best kept in what is called a brush safe. A 
deep wooden pail, with nails driven in its sides at different distances 
from the bottom, and with a close cover, makes a good receptacle 
for brushes. The brushes have holes in their handles, or loops of 
cord tied to them, and are hung on these nails; their bristles dip into 
some turpentine or oil in the botttom of the pail; they are so hung that 
they do not dip into the liquid above where the bristles project from 
the binding. If brushes are left standing on the bristles on the bottom 
of a vessel, they soon become one-sided and distorted in shape. Tin 
brush-safes may be bought of any large dealer in brushes. 

A brush which has dried with paint or varnish in it, may be 
recovered by soaking it in a non-alkaline varnish-remover. This will 
in time soften it so that it may be used again, but it is not improved by 
such treatment. Brushes used in shellac should be washed out with 
alcohol instead of turpentine or benzine. No brush is good unless it is 
clean. 

Fillers. Fillers are of two kinds — paste and liquid. Paste 
fillers are something like a very thick paint, and are composed of some 
solid powdered substance, usually silica or powdered quartz, mixed 
with a quick-drying varnish thinned with turpentine or benzine. 
This is applied to the dry surface of the wood with a stiff, short-bristle 
brush, or is put on with a clean, white cotton cloth, and well rubbed into 
the pores of the wood. After half an hour or so, the surface of the 
wood is wiped off with a wad of excelsior or a clean cloth or a piece of 
felt. A liquid filler is a quick-drying varnish; and most of the liquid 
fillers on the market are cheap rosin varnishes loaded with dryers, 
and should never be used. Paste fillers are the best in almost all 
cases. 



PAINTING 



HOUSE PAINTING 
Inside Work. All window and door frames, whether they are to 
be finished with paint or varnish, should receive a good coat of paint 
made with some cheap pigment, such as iron oxide, and boiled oil, 
applied to the back of the frame, before they are brought from the 
shop to the house; this prevents the absorption of moisture and hin- 
ders decay. If they are to be painted, they should receive a priming 
coat in the shop, if possible; if not, it should be applied as soon as prac- 
ticable. The priming coat is composed of white lead and boiled oil or 
raw oil, with five to ten per cent of dryer; and should be almost all 
oil, with very little pigment. Turpentine is not a good thing in a 
priming coat, because the object is to fill the pores of the wood, and 
turpentine evaporates. As soon as this is dry to the touch, all holes 
are to be filled with putty. The best putty for this purpose is white 
lead putty, made by mixing a little raw oil with dry white lead, 
or by adding dry lead to paste lead until it is of the right con- 
sistency. This kind of putty hardens quickly as compared with 
common putty, and is the best for this purpose. A steel putty-knife 
should not be used on interior woodwork, as it is almost certain to 
scratch it; a hardwood stick, suitably shaped, should be used. All 
cracks, joints, and nail-holes shoukl })e carefully filled. All knots 
and sappy places should be varnished with shellac varnish; this pre- 
vents the pitch and moisture from attacking the paint. The shellac 
should be applied where it is needed, before the priming coat. The 
priming coat should be given time to get quite dry; at least a day —two 
days, if possible; and a week is better yet. Then it is ready for the 
second coat. This should contain a considerable amount of turpentine. 
If no turpentine is used, the surface is likely to be glossy, antl the next 
coat of paint will not adhere well; l)ut by replacing part of the oil with 
turpentine, we get what painters call a fiat coa/— that is, one which is 
not glossy; if this is made from paste lead or any paste paint, it can 
be produced by thinning the paste with a mixture of oil and turpentine 
in equal proportions; some painters prefer one-third oil and two- 
thirds turpentine. This is for inside work only. This coat should 
be allowed to dry thoroughly; if it takes ten hours for the paint to be 
dry enough to handle, then at least four times ten hours additional 
should elapse before the next coat is applied; this is a good general rule; 
and as much more time as possible should be allowed. If the finish 



10 PAINTING ' 

« — 

is to be ordinary oil paint, the next coat may be paint, thinned with 
about half as much turpentine as before, or with no turpentine at all. 
In the latter case, when the coat is thoroughly dry, it must be carefully 
examined, and, if glossy, it should be rubbed with something to take 
off the gloss; curled hair is often used, or a light rubbing witii j)umice 
and water. I'hen the final coat, which has no turpentine in it, may be 
applied. 

But if the finish is to be with an enamel paint, the second coat, 
when c|uite dry, should be very lightly sandpapered with fine sand- 
paper, and the third coat should be of like composition to the second, 
treated the same way; then the enamel paint is applied. For a really 
first-class job, when this is cjuite dry, it should be rub])ed down with 
curled hair or pumice and water, and another coat of enamel put on. 
This may be left with the natural gloss if desired; or it may be rubbed 
with pumice and water to a flat (dull) surface. 

Painting Plastered Walls. Old plastered walls may be painted 
with oil or enamel paints as though they were wood, remembering that 
the priming coat will have almost all of its oil absorbed by the plaster. 
New plastered walls do not take paint well, on account of their alkaline 
character, which gradually disappears with exposure to the atmos- 
phere. It is well to let a wall remain unpainted at least a year. But 
if it is necessary to paint a freshly plastered wall, the wall is prepared 
by some painters by washing it with a solution of sugar in vinegar, 
the sugar uniting with the lime to some extent; or — more commonly — 
by washing it first with a strong solution of common alum and then 
with a solution of soap. After this is dry, it is washed with clean 
water, allowed to dry, and then painted. The alum and soap form an 
insoluble compound which closes the pores of the plaster to some ex- 
tent, and prevents the lime from acting on the paint. 

Outside Work. Exterior paints are more elastic, as they need 
to be far more lasting, than those used on interiors, since the effect of 
exposure to the sun and rain destroys paint more than almost any- 
thing else does. Paint on the interior of a house will last almost 
indefinitely; but on the outside the best paint is not very durable. The 
surface, if new, should be cleaned by brushing; knots should be 
shellacked: after which the priming coat should be applied. This 
may be the same paint which is selected for the finish, only thinned 
with l)oiled oil (or raw oil and dryer), using one to one and a-third 



PAINTING 11 



gallons of oil to each gallon of paint. The reason why ordinary paint 
may not be used as a primer, is that the wood absorbs the oil, leav- 
ing the pigment as a comparatively non-adhesive powder on the sur- 
face, from which the next coat will probably peel off. The next step 
is to putty up all nailholes and other defects. For the second coat, 
many experts advise the addition of half a pint of turpentine to the 
gallon of paint; others make no addition to it. The third coat is 
applied after the second is thoroughly dry; if a week or a month can 
elapse between these coats, so much the better. 

Repainting. If the old paint has been on a long time, it is liable 
to be permeated by minute cracks, which admit moisture to the surface 
of the wood and loosen the paint. If now we paint over this, the new 
paint, which shrinks in drying, tends to pull off the old paint, and of 
course the whole peels off in patches. If the old paint is in this state, 
it must be removed before the new paint is applied. This can be 
done by burning ojf. For this work a 'painter's torch is required, 
which is a lamp burning alcohol, gasoline, or kerosene, and is so con- 
structed that a blast of flame can be directed against the surface. This 
melts or softens the old paint, which is then immediately scraped off 
with a steel scraper. The paint is not literally burned, but is softened 
by heat so that it can be scraped off. In some cases it is sufficient 
to remove as much as possible with a steel brush; this is a brush like 
a scrubbing brush, with steel wires instead of bristles, and, when 
vigorously used, will take off the loose paint. 

Old paint, however, is not always in this condition. If it adheres 
well, it may be cleaned with an ordinary scrubbing brush and water, 
and when it is quite dry, the new paint may be applied. Sometimes 
the paint seems in good condition, only it has faded and lost its luster; 
in such cases a coat of boiled oil, or raw oil with dryer, is all that is 
needed. 

It is well to paint the trim — that is, the window-casings, door- 
casings, corner-pieces, and the like — before painting the body of the 
house; then the paint can be applied to the flat surfaces more neatly 
than is otherwise likely to be done. Paint should be applied in thin 
coats, well brushed on; it is not unusual to see paint come off from 
re-entrant angles while it is still, good on flat surfaces, because it was 
difficult to brush the paint properly in those places. There is a great 
difference in durability between a thin paint flowed on with a large. 



12 PAINTING 

m 

flat brush, and one of proper consistency well brushed out with a brush 
of medium size. In all painting on wood, it is desirable to brush it on 
with the grain of the wood ; and by painting only a few boards at once, 
we may avoid laps by painting the whole length. Rough surfaces 
hold paint better, and more of it, than smooth. A gallon of paint will 
cover, one coat (on a painted or well-primed surface), about GOO scjuare 
feet, not flowed on, but well brushed out in a thin film. The priming 
coat will not cover more than 300 or 400 square feet to the gallon. In 
measuring the outside of a house for surface, make no deductions for 
doors and windows; if the trim is to be painted a different color, from 
one-sixth to one-third of the paint will be required of that color. 
Paint should be stirred frequently while using. A coat of dry paint is 
from 5^-J -Q to Y, uW of an inch in thickness. 

Rocf Painting. Roof paints should contain a larger proportion of 
oil to pigment than other paints, and less dryer (or none at all). 
Many think that the addition of ten to twenty per cent of fish oil to a 
paint for roofs is advantageous; fish oil greatly retards drying and 
prevents the paint from becoming brittle. Tin roofs, if new, should 
be thoroughly scrubbed with soap and water, or with pieces of harsh 
cloth, such as burlap, well wet with benzine. They may then be 
painted. 

Paint dries relatively fast on roofs; but as a roof paint is very 
slow-drying, plenty of time must be allowed between coats. A new 
roof should receive three coats. ^Nletal gutters and spouts are to be 
treated the same way. Do not forget that new tin or galvanized iron is 
difficult to paint; have it very thoroughly scrubbed, even though it 
looks perfectly clean, and then rub the paint on well with the brush. 
Metal spouts will usually be painted the same color as the wall of the 
house. 

Sometimes shingle roofs are painted with fireproof paint. This 
is not really fireproof, but considerably retards the spread of fire, after 
it has become thoroughly dry; when fresh, it does not even do that ; nor 
does it have much effect after it has been on a year or so. It may be 
made by adding to a gallon of any good paint about a pound of 
powdered boracic acid. When strongly heated, this material fuses 
and forms a sort of glass, which keeps the air from the wood. It is 
after a time washed out by the rain. 

Canvas roofs are prepared in the following manner: The canvas 



PAINTING l.ri 



(10-ounce duck is often used) is first nailed down, care being taken to 
draw it tight; it will show some wrinkles, but these are not to be allowed 
to accumulate to form a large wrinkle or fold. Then the canvas is 
thoroughly wet; it shrinks, and all the little wrinkles disappear. It is 
a common practice to paint it while it is still wet, this being an excep- 
tion to all other practice; but some wait until it is dry. The writer 
has been accustomed to the latter method, and has not found that the 
canvas shows wrinkles on drying, while the results are all that can be 
desired. A well-painted canvas roof is very durable and satisfactory. 

PAINTING STRUCTURAL METAL 

Steel is a more perishable material than wood, and more difficult 
to paint. Without regular expenditure for maintenance, wooden 
bridges last longer than steel ones; there are wooden roof beams a 
thousand years old ; and iron roofs are so short-lived that they are used 
only over furnaces and the like, wdiere wooden ones would take fire. 
The painting of structural steel is therefore important; and it is also 
difficult, if we are to judge by results. 

In the first place comes the preparation of the surface. When 
we paint wood, we have the surface clean and dry; and then we soak 
it with oil, so as to have the paint bound to it in the most intimate 
manner. Iron and steel, on the other hand, always come to us dirty, 
and covered with oxide; and as the surface is not porous, the paint 
does not penetrate it, but has to stick on the outside the best way it can. 
If we paint over the dirt and scale, and that ever comes off, the paint 
comes off with it; if the metal is actively rusting, and w^e paint over the 
rust, the corrosion is perhaps made slower, but it does not stop. 

Air and moisture cause rust; if we can keep them away, the metal 
will last; but, unfortunately, all paint is very slightly porous, and if 
exposed to the weather it in time deteriorates. The most essential 
thing in painting metal is to get the paint on the metal, not on an inter- 
mediate coating. 

There are only two ways to clean steel perfectly. One is by 
pickling it in dilute acid (usually 10 to 20 per cent sulphuric acid), 
followed by washing to remove the acid ; and the other is by the use 
of the sand-blast. Neither of these processes is available to the ordinary 
painter, who must do the next best thing. This is to remove absolutely 
all dirt and all loose scale and oxide. First clean off the dirt, if anv, 



14 PAINTING 

• •- — 

with brushes, as it would be cleaned off any other surface. Then, 
with scrapers and steel-wire brushes, clean off all the scale which will 
come off. If there is any new rust (not mill scale), it must be well 
scraped out and cleaned off. This is indispensable. When this is 
done, immediately paint it, before it begins rusting again. 

One of the most popular materials for a first coat is red lead in 
oil. This must be mixed on the spot, shortly before it is used, because 
it will harden into a cake in the pail or can if allowed to stand very 
long. From 30 to 33 pounds of dry red lead is to be mixed with each 
gallon of oil — not less than 28 in any case. This is immediately painted 
on the metal; if it is put on in too thick a coat, it will run and be uneven. 
Some use raw oil, others boiled oil; it does not make much difference 
w^hich is used. The paint dries rapidly; and as soon as it seems hard, 
a second coat of the paint can be applied. Red lead is different 
from all other paints in this, that it will finish hardening just as well 
away from the air. This is because it does not dry by oxidation, as 
other paints do, but by the lead combining chemically with the oil, 
just as water combines with Portland cement. In the opinion of ths 
w^riter, red lead should have one or two coats of some good paint, other 
than red lead, over it. But red lead is not the only first coating which 
may be used. Any good paint may be used — a good graphite paint, or 
other carbon paint, or some of the varnish-like coatings containing 
linseed oil and asphaltum which are made for the purpose. It is 
important, in using any of these, to let plenty of time for drying elapse 
between coats. Not less than two coats is permissible, and three are 
desirable. 

Projecting angles, edges, and bolt and rivet heads arc the places 
which first show rust through the paint. This is partly because the 
brush draws the paint thin at such places. To overcome this, it is now 
becoming common practice to go over the work after the first coat, 
and paint all edges for about an inch from the edge or angle, and all 
bolt and rivet heads, with an extra or striping coat; then, when the 
second coat goes on over the whole, there is the equivalent of two 
full coats everywhere. 

Painting on iron, as on wood, should be done in dry weather, 
when it is not very cold^ — at any rate not below 50° F. Full, heavy 
coats should be used, and well brushed on. Care must be taken to get 
the paint into all cracks and corners. 



PAINTING 15 



VARNISH 

A varnish is a liquid made to be applied to a surface in a thin 
film, which, on exposure to the air, hardens into a protective coating 
that is usually glossy and almost transparent. There are two principal 
classes— spirit and oleo-resinous varnishes. 

Spirit varnishes, of which shellac^ is the most important, are made 
by dissolving a resin (or sometimes some other substance) in a volatile 
solvent, such as alcohol. They dry by evaporation, the solvent going 
off and leaving the resin spread out in a thin film, the liquid or vehicle 
having really served as a mechanical means of spreading the resin over 
the surface. Shellac is a resin which comes on the market in lars:e, 
thin flakes. It may be dissolved in denatured (or any other) alcohol 
in the following manner : 

Put the alcohol in an earthenware jar, and weigh out five pounds 
of gum shellac for each gallon of alcohol. Just before leaving at 
night, carefully and gently drop the shellac, little by little, into the jar 
of alcohol, then put on the cover and leave it until morning. Do not 
on any account stir it. In the morning the flakes of shellac will be 
soaked and swollen; but if you had stirred them in, the night before, 
they would have stuck together in lumps. Now, during the day, stir 
the mass with a wooden stick once every hour or so ; do not put any 
metal in it, especially iron; one iron nail will spoil the color of a whole 
barrel of shellac. By the next morning — perhaps before — the shellac 
will be ready for use. It does not make a clear solution , because the 
gum shellac contains some wax, which does not dissolve, and so the 
varnish is milky or cloudy; it is, however, ready for use. As the 
alcohol is volatile, the jar should be kept covered; and after it is 
made, the varnish should be put in glass bottles or clean tin cans. 

There are many grades of shellac gum, the best being known by 
the letters D C; but there are others nearly as good. The common 
shellac is brownish yellow, and is called orange shellac; this is the natu- 
ral shellac color. White shellac is made from this by bleaching with 
chlorine; but it is not of so good quality as the unbleached; it has, of 
course, the advantage of being much paler in color. WTiite shellac 
gum will, on long standing, sometimes become insoluble. Shellac 



♦Note. — By some painters, the term "varnish" is never used to include shellac. 
There is, however, no valid, objective reason for thus limiting the use of the term. 



16 PAINTING 

• 

varnish may be thinned with alcohol, and often this is necessary. 
Shellac is too often adulterated with common rosin, which greatly 
lessens its value. This is easily detected by a chemical test. 

Damar is a white resin which is soluble in spirits of turpentine- 
five or six pounds of resin to a gallon of turpentine. It is the most 
nearly colorless varnish we have, but never becomes very hard. It is 
used to a considerable extent as a vehicle for white lead and zinc, to 
make a very white enamel paint. It is not durable if exposed to the 
weather. 

More important than spirit varnishes are the oleo-resinous var- 
nishes, which consist of certain resins dissolved in linseed oil, the mixture 
being thinned with turpentine or benzine. In making these, the resin 
is put in a copper kettle and heated until it is thoroughly melted; then 
some hot oil is added to it, and the mixture cooked until the whole is 
thoroughly combined. The kettle is then taken from the fire, and 
when partly cool, the turpentine is stirred in. The resin makes the 
film hard and lustrous, and the oil makes it tough. Thus the larger 
the proportion of resin, the harder and more brilliant will be the film; 
the larger the proportion of oil, the tougher, more elastic, and more 
durable it will be, and the slower it will dry. ]Most of the color of varnish 
comes from the resin; the paler this is, the paler will be the varnish. 
The pale gums are higher in price than the dark ones, but are no better 
in any respect except color. Dark varnishes may be just as good 
(except in color) as pale ones — in fact may be better, for the dark 
resins are often harder and better than the pale ones of the same sort. 
The hard and quick-drying varnishes are suitable for furniture ; the 
medium, for interior house-varnishes; the slow and elastic, for exposure 
to the weather. 

Varnishing. The wood should be dry. For this reason it is 
better, if necessary to clean it, to avoid washing as much as possible, 
using sandpaper instead, which will also make it smooth. Of course 
the carpenter is supposed to do this, but the painter must not neglect 
it on that account. When in proper condition, it first receives, if it is an 
open-grain w^ood, a coat of paste filler. The open-grained woods in 
most common use are oak, chestnut, and ash. The woods classed as 
close-grain woods are white pine, maple, birch, yellow pine, white- 
wood, cherry, and sycamore. These latter do not need filling. If 
filler is used, it should be well rubbed in with a short, stiff brush; and 



PAINTLXG 17 



when it has set, say in fifteen to thirty minutes, it is rubbed off with a 
handful of excelsior, rubbing across the grain, and rublMng hard, so as 
to force the filler well into the pores of the wood. Then it should 
stand 24 to 48 hours. 

When purchased, a paste filler is too thick to be used with a brush, 
and must be thinned with turpentme or benzine; at the same time it 
may be stained to any desired color with an oil or varnish stain. These 
stains can be purchased of any desired color. If a close-grained wood 
is under treatment, the first thing is to apply a stain if it is desired to 
stain the wood ; but it is common practice to finish in the natural color. 
Stains usually require a good deal of thinning before using; the amount 
of thinning will determine the depth of color. Water stains are seldom 
used, as they tend to raise the grain of the wood. 

In cleaning off the filler, be careful to clean out corners and mould- 
ings, usmg for this purpose, properly shaped hardwood sticks; do not 
use any steel tool. 

Where rooms are to be finished in the natural color of the wood, 
it is nevertheless a common practice to stain the window-sashes; a 
cherry or light mahogany stain is often used. Fillers are sometimes 
used on close-grain woods; but this is not advisable, as they tend to 
prevent the varnish from getting a good hold on the wood. 

Next comes the varnishing. Window-sills, jambs, inside blinds, 
and other surfaces exposed to the direct rays of the sun, are to be 
treated as exterior woodwork, and are not varnished with the ordinary 
interior varnish used on the rest of the work. The floors also are left 
out of account for the present. The rest of the woodwork receives its 
first coat of varnish ; apply it, as much as possible, with the grain of the 
wood, brushing it out well in a thin coat. The varnish ought to dry 
dust free (;'.e.,so that dust will not stick to it) overnight; but at least 
five days should elapse between coats. When dry, it should l)e rubbed 
with ciu'led hair or excelsior enough to remove the gloss, so that the next 
coat of varnish will adhere properly; a better result will be had if it is 
lightlv sandpapered with GO paper. The second coat is treated like 
the first. The third is not sandpapered, but rubbed with curled hair; 
the fourth or finishing coat may be left with the natural gloss, or, if pre- 
ferred, it may be rubbed with fine pumice and water to a smooth, dull 
surface. For this purpose the varnish dealers sell felt, about an inch 
thick, which is well wet in clean water; a little dry pumice powder is 



18 PAINTING 



put on it; and the rubbing is done with this. The varnish must be 
quite hard and dry before this is attempted. Varnishing, if properly 
done, is slow work; that is, much time must be allowed for each 
coat to dry thoroughly. 

The varnish which is used on interior woodwork should not dry 
too quickly; it should dry enough over night so that dust will not stick 
to it, and in twenty-four hours should be hard enough to handle freely; 
but if a chair, for example, were varnished with it, it would not be 
entirely safe to sit on it for a week. It should, however, finally become 
perfectly free from tack, which it will not do if it is a rosin varnish. At 
present prices (and it is not probable that they will ever be lower) var- 
nishes for interior woodwork are sold, according to color and quality, 
at prices ranging from $2.50 to $4.00 a gallon. It is in the highest 
degree inadmissible to use a cheap varnish for undercoats ; theouter coats 
will crack if this is done. A good varnish that dries too quickly, such 
as what is called a rubbing varnish, or one intended for furniture, has 
not the durability needed for this work. It is economy to use a good 
varnish. The writer has in mind a house which was properly var- 
nished eighteen years ago and has been constantly occupied by a large 
family, yet the varnish is still in fair condition ; if it were lightly sand- 
papered and one new coat applied, it would be like new — as good as 
it is possible for a surface to be. Cheap rosin varnishes never look 
well, even when new, never keep clean, and deteriorate rapidly. 

Shellac. Interiors are sometimes finished with shellac. This 
varnish is not used on exterior work, but it is a good varnish for inter- 
iors. All varnishes containing oil darken the color of wood ; but white 
shellac is comparatively free from this objection; at any rate it does it 
less than anything else. Orange shellac is a dark varnish, and even 
white shellac darkens with age to an appreciable degree. Orange 
shellac is more durable than white, and should be used wherever 
admissible, rather than white; but it is usually necessary to use white 
shellac for this service. If shellac is made up as heavy as has been 
described — five pounds to a gallon of alcohol, and this is the standard 
— it should be thinned consitlerably with alcohol before using on inte- 
rior woodwork. It must be applied in thin coats, and gi^■en plenty of 
time to dry. It is very deceptive about this; it appears to be dry and 
hard in an hour, and it is hard enough to handle freely; but if we apply 
coat after coat, even six hours apart, we shall find that the wood is 



PAINTING 19 



finally covered with a waxy mess which will be the source of nothing 
but trouble. The first coat sinks rapidly into the wood ; a second coat 
may be applied six hours later; but after that, allow two days at least 
between coats. Shellac makes a very thin coat; so it is necessary to 
apply a large number of coats, at least twice as many as of oleo- 
resinous varnishes, to get a sufficient thickness of coating. Because 
of this labor, shellac is an expensive finish; but it is handsome fnd 
durable. The treatment of it, as regards rubbing, etc., is the same 
as has been described for other varnish. 

Varnish makers usually advise that shellac should never be used 
as a priming coat for other varnish; this is probably because they wish 
to sell more of their own goods, for shellac is really an excellent first 
coat, except for exterior work, where it should not be used. Of course, 
wood should be filled before shellacking, the same as for other varnish. 
Varnish does not, however, wear well over a heavily shellacked sur- 
face. Shellac makes a good floor varnish, discoloring the wood very 
little, and wearing fairly well. After the floor has been well varnished 
with it, very thin coats, applied rather frequently — say every one to 
four months, according to use — will keep the floor in fine condition ; 
and after applying one of these thin coats (of thinned shellac), it will 
be dry enough to use in an hour. This can be applied with a very 
wide, flat brush, and a man can go over the floor of an ordinary room 
in a few minutes. Shellac brushes should be washed out with alcohol 
immediately after using. 

Exterior Varnishing. Varnishes dry much more rapidly out of 
doors than within, so that it is practicable to use more elastic and dur- 
able materials. The conditions, in fact, are so severe that the best 
are not good enough. In the first place, do not use any filler on 
exterior work; it will probably crumble and come out. Do not use 
shellac; as an undercoat exposed to the hot sun, it will soften and 
blister. Use only the best spar varnish, such as is made for varnish- 
ing the spars of yachts; fill the wood with it; sandpaper lightly 
between coats, just enough so that each succeeding coat will take 
hold w^ell ; finish with a coat well flowed on ; and leave it with its 
natural gloss, which is more lasting than a rubbed surface. This is 
the treatment for hand-rails, outside doors, inside blinds, window- 
sills and jambs, and everything exposed to the direct sun. Hand- 
rails and outside doors should be refinished every year; varnish will 



20 PAINTING 

. ^ — 

not last on an outside door more than one-twentieth as long as it will 
on an inside door. Never use interior varnish for outside work. 

ENAMEL PAINTS 

Varnishes are all more or less brownish yellow or yellowish brown. 
Therefore a coat of varnish applied over a paint obscures and changes 
its color to some extent. To overcome this as much as possible, the 
varnish, instead of oil, is mixed with the pigment, as a vehicle. In 
this way the pigment comes to the surface and displays its color. 
These paints, if made with good varnish, are durable; the method of 
application has already been described. If necessary to thin them, 
do it with spar varnish instead of oil; a good interior varnish may be 
used, l)ut it injures the flowing quality of the paint somewhat. 

White lead and zinc are sometimes mixed with damar varnish. 
This makes the whitest enamel paint, but it never gets very hard, 
never has much luster, and is not very durable. It is very white, is 
easily applied, and dries (|uickly. 

A NEW VARNISH FINISH 

A method of finishing open-grained interior woodwork, which has 
been practiced for a few years, consists in first staining the wood with a 
water-stain — dyeing it, usually — and then, when it is dry, filling the 
pores of the wood with a paste filler which has been colored by the 
addition of a pigment. For example, the wootl may receive a stain 
of any dark color, and the wood-filler be mixed with white lead. This 
shows the open or porous part of the grain in white on a dark back- 
ground. By using artistic combinations of color in the stain and filler, 
very beautiful effects can be produced, and this finish has been used in 
some of the most handsome and costly public and private buildings. 
Thus, if a room is to be decorated in green, the woodwork can be made 
to harmonize with the j)revailing color. An oil stain must not be used 
on the wood, as it will not work well with the filler. The colored filler 
is applied and rubbed off in the same way that any paste filler is used, 
and then the varnish is applied over it in the usual way. 

FLOOR FINISHING 

The primary trouble with floors is that people walk on them. If 
thev did not, there woukl be no trouble at all. Four coats of varnish. 



PAINTING 21 



or even paint, having an aggregate thickness of less than one one- 
hundredth of an inch, will not last indefinitely under the wear of nail- 
shod heels. 

Probably the simplest treatment for floors is painting them. The 
paint should contain a large proportion of a hard oleo-resinous 
varnish; an ordinary oil paint is not hard enough. If an oil paint is 
used, it must be heavily charged with dryer, for a floor paint should 
dry in twelve hours. Good quick-drying floor paints are in the 
market. 

Floors of choice w^ood, how^ever, are not usually painted ; they may 
be either varnished or waxed. If they are of oak or other open-grained 
wood, they must be filled with a paste filler; otherwise the varnish is 
applied directly to the wood. Floor varnish is quicker in drying, and 
harder than interior finishing varnish, but should not be so hard as to 
be brittle; rubbing varnish is too hard. If the floor is to be stained, 
this is done with an oil stain before varnishing; if it is a floor which 
has previously been varnished, so that the stain will not penetrate the 
wood, the stain may be mixed with the varnish, although the effect is 
not then so good. 

Floor wax is not made of beeswax, but of a harder vegetable wax, 
and is sold by all paint dealers. The floor should receive one coat of 
shellac; then the floor wax maybe rubbed on with a stiff brush, and 
when it is dry, which will be in a few hours, it may be polished by 
rubliing with a clean cloth or with a heavy, weighted floor brush made 
for the purpose. It should receive another coat every week until four 
or six coats have been applied; after this a little of the floor wax, 
thinned if necessary with turpentine, should be applied often enough 
to keep the floor looking well. Alkalies dissolve the wax, and in 
cleaning the floor only a little soap should be used in the water with 
which the floor is washed. A wax finish kept polished with a polishing 
brush, is the handsomest surface than can be obtained for a floor; but 
it is so slippery that it is somewhat dangerous. It does not discolor 
the wood. Interior trim (but not hand-rails) is sometimes wax- 
finished. This finish requires a good deal of care, as it is likely to 
catch dust; otherwise it is handsome and durable. 

Old floors which require cleaning and revarnishing should have 
the old varnish or paint removed by a good varnish-remover, one of the 
modern sort, free from alkali. This is painted over the surface, and, 



22 ■ PAIXTINC; 

• — 

after a short time, removed with a scraper. The last of the varnish- 
remover is taken out with a rag wet with turpentine or benzine, care 
being taken that there is no fire of any sort in the room or any neighbor- 
ing room. This will not only take off the old varnish, but the old filler 
also; and the floor must be treated like a new floor. Any stains on the 
floor may be treated with a hot solution of oxalic acid, one part to ten 
of water; when the stains disappear, wash Avell with clear water; let 
the floor dry a day; sandpaper; and it is ready for varnishing again. 
This treatment — removal of old paint or varnish by a liquid varnish- 
remover — is applicable to all varnished or painted work. The outside 
of a house could have the old paint taken off in this way, but hurning 
off is cheaper and quicker. These varnish-removers are mixtures of 
benzole, acetone, alcohol, and other liquids, and the best of them are 
patented. 

ALUMINUM AND BRONZE PAINTS 

Radiators and pipes are often painted with aluminum or bronze 
paints. These consist of metallic powders, in fine flakes, mixed with 
some varnish — usually with a pyroxylin varnish, which is a thin solu- 
tion of a variety of gun-cotton in a suitable solvent, generally acetate of 
amyl. If one of these paints — which smell somewhat like bananas — 
becomes thickened in the can by evaporation, it can usually be thinned 
with acetate of amyl, if some of the special thinner cannot be had; 
brushes can be washed out in the same. A good aluminum paint is 
durable, even exposed to the weather. One coat is usually enough, 
two certainly so. 

GLAZING 

House painters are usually expected to understand the art of 
setting window-glass; it is not difficult to learn, (rlass is classified as 
sheet or cylinder glass and plafc glass. Sheet glass is made, at the 
glass works, by blowing a ((uantity of glass, first, into a hollow globe; 
then, by more blowing and manipulation, this is stretched out into a 
hollow cylinder perhaps a foot in diameter and five feet long; this 
cylinder (whence the name "cylinder glass") is cut open, and, after 
reheating, is flattened out into a sheet, whence the name "sheet glass;" 
after annealing, it is cut up into convenient sizes. It is made of two 



PAINTING 23 



thicknesses — single thick, which is about one-sixteenth of an inch; 
and double thick, one-eighth of an inch; but it does not run perfectly 
uniform. All sheet glass contains streaks, bubbles, and specks of 
dirt, and is more or less irregular or wavy in its surface; and in respect 
to this it is graded as first, second, and third quality; in American glass 
these grades are usually marked "AA," "A," and "B;" and anything 
poorer than "B" is called stock sheets. Foreign glass is not thus 
marked, each maker having his own arbitrary marks. Single-thick 
glass is used for sizes not greater than about 28 by 34 inches; double- 
thick, up to 40 by 60. For larger sizes, plate glass only is used; but 
of course either plate or double-thick can be used for small sizes, if 
desired. 

Plate glass is cast in plates; the liquid glass is poured out on an 
iron table, about 15 feet wide and 25 feet long, and smoothed down to a 
uniform thickness of half or five-eighths of an inch by passing a roller 
over it, like rolling pie-crust ; after this it is ground down with sand, 
emery, and polishing powder to a quarter or five-sixteenths of an inch 
in thickness. It is therefore much more costly than sheet glass, but 
is also more perfect. 

Crystal is a very thin plate glass, about one-eighth of an inch thick, 
and is used where ordinary plate is too heavy, as in movable sash. It is 
the finest of all window glass. There are two grades of plate glass, 
known as glazing (for windows) and silvering (for mirrors), the latter 
being the best. In the first place, the sash is prepared for the glass. 
It must receive a priming coat; if it is to be painted, it is primed with 
white lead and boiled linseed oil, the mixture having very little or no 
turpentine added; if it is to be varnished, it is primed with boiled oil 
alone. If it is not primed, the putty will not stick; the wood will draw 
the oil out of the putty and leave it crumbly. Next, the glass is fitted 
to the sash. It is cut either with a glass-cutter's diamond or with a 
wheel cutter, the latter being a little sharp-edged steel wheel set in a 
handle. If well made, the wheels may be bought separate and are 
replaceable. The wheel cutters are generally used on sheet glass; but 
plate glass is cut only with a diamond, which makes a deeper cut. 
The wheels are kept w^et with kerosene; the workman has a litde bottle 
or cup of kerosene on the bench, and dips the wheel in it. 

The glass being cut to the right size, a layer of putty is spread, 
with the putty-knife, along the recess in the sash where the glass is to 



24 PAINTING 



rest. This Is called bedding the glass, and should always be done. 
It is not inicommonly omitted with pine sash; but it absolutely must be 
done with all hardwood sash, metal or metal-lined sash, and for all 
plate and crystal glass; and it ought to be done in all cases. Then the 
glass is gently pressetl into place, after which it is fastened with glaziers' 
points, which are triangular bits of metal. No. 2 points are used on 
single-thick, and No. 1, which are larger, are used on double-thick 
glass; they are put in 9 to 12 inches apart. They are driven, not with 
a hammer, but with the thin side of a two-inch chisel, the flat side of 
which lies on the glass, the edge of the chisel away from the surface 
so as to avoid scratching it. The chisel is also useful for adjusting the 
position of the pane ; if it is smaller than the sash, it is so placed that 
when the sash is in its natural upright position the pane of glass will 
rest with its lower edge bearing on the wood. The points are com- 
monly of zinc, which bends easily; and when the pane is properly 
placed, if there is on one side a space between it and the wood, the 
chisel is held over this crack, and with its edge an indentation or crimp 
is made in the little triangular zinc point which has already been 
driven; this crimp prevents the glass from sliding back against the 
wood. This is the reason zinc is used for the points; it will bend. 
Steel points are sometimes used for plate glass, because of their greater 
strength, the glass being heavy. To drive through the sheet metal of 
metal-covered sash, steel slugs are used; these are about g^Q inch thick, 
about I inch long, and ^'^ "ich wide at the wude end, triangular, and 
sharp-pointed. 

There is a machine for driving points, but it is not much used 
except on small glass set in soft-wood sash. 

The glass being properly secured by points, it is ready for putty- 
ing. To do this, the professionals set the sash up in a nearly vertical 
position on an easel; the glass is puttied on the right-hand side and 
across the bottom; then the sash is turned the other edge up, and the 
operation is repeated. This finishes the work. 

The most important things about glazing are to use a sufficient 
number of points and to use good putty. Ordinary (pure) putty is 
made of whiting, which is pulverized chalk, mixed with enough linseed 
oil to give it the consistence of stiff dough. The workman can make it 
from these materials with his hands; everyone can make his own putty. 
As a matter of fact, however, the putty of commerce is made by ma- 



PAINTING 25 



chinery; and also, as a matter of fact, it is in general abominably 
adulterated. It would seem as though whiting and linseed oil were 
materials cheap enough; and in reality putty can be sold for about 
three cents a pound, or sixty dollars a ton; and a dollar's worth will 
putty all the glass in an ordinary house. Pure putty, however, is 
almost impossible to get. INIarble dust is substituted for whiting, 
and a mixture of rosin and mineral oils for the oil, and the cost reduced 
about half. It is the use of this miserable stuff which causes nine- 
tenths of the troubles with windows. If the glazier cannot be sure of 
his putty otherwise, he should make it himself. 

The best putty for glazing is a mixture of pure whiting putty with 
one-tenth white lead putty. This makes it set a little more quickly, 
and it becomes harder. Pure white lead putty gets too hard; it is too 
difficult to remove it in case of breakage of glass. 

If the glass has not been bedded in putty, it is customary to go 
around the indoors side of the glass, and crowd some putty into the 
crack between it and the sash. This is called 6flcA-mf/ the glass. Large 
plates of plate glass are not puttied, but are held in place with strips 
of moulding nailed on the sash, in which case the crack between the 
glass and the moulding is backed with putty. 



EXAfllNATION PAPER 



PAINTING 



Read carefully: Place your name and full address at the head of 
the paper. Any cheap, light paper like the sample previously sent you 
may be used. Do not crowd your work, but arrange it neatly and legibly. 
Do not copy the answers from the Instruction paper; use your oivn words, so 
that we may be sure that you understand the subject. 

1. What is the difference between raw and boiled oil? When 
is one preferable to the other? 

2. What would you consider a good brush outfit for painting 
and varnishing the interior woodwork and exterior finish of a modern 
frame dwelling? 

3. How would you make your own putty if you could not buy 
a satisfactory grade? 

4. Describe the principal ingredients used as pigments. As 
vehicles. 

5. What are thinnersf Dryersf Fillersf 

6. How are painters' brushes kept in good condition? 

7. How are paints adulterated? 

8. Describe the process of mixing the successive coats of 
paint for ordinary interior (not floor) and exterior woodwork. 

9. Describe the process of preparing the woodwork and 
applying the successive coats of paint in ordinary interior (not floor) 
and exterior work. 

10. What points require particular attention in the repainting 
of an old job? 

11. Describe the process of painting a plastered wall. 

12. Describe the material and methods of work in roof painting. 

13. What is enamel paint? How would you do a job of 
enameling the woodwork, say, in a bathroom? 

14. Describe in detail the process of painting structural metal. 

15. How are varnishes classified? 

IG. Describe the method of preparing and applying shellac 
varnish. 

17. Describe in detail the method of preparation and appli- 



PAIXTIXG 

* 

cation of varnish (not shellac) in the case (a) of interior woodwork 
(not floors) ; (h) of exterior woodwork. 

IS. What method in your opinion, gives the best finish to a 
floor (a) of pine; (h) of ash? Describe the process in detail. 

19. Distinguish the different kinds of glass used in windows 
and doors. 

20. In window glazing, describe in detail the method of pre- 
paring the sash and inserting the glass. Is large plate glass put in 
in the same way as ordinary window glass? 

After completing the work, add and sign the following statement: 
I hereby certify that the above work is entirely my own. 
(Signed) 



JUN 13 1908 



/ 



